In the 1970s, it was discovered that Raman scattering of analyte molecules, upon irradiation with optical energy, can be enhanced as much as 106 to 107 when the molecules are adsorbed on noble metals such as silver, copper, and gold. This phenomenon is known as surface enhanced Raman spectroscopy (SERS). A SERS structure generally includes a metal layer formed on a substrate and is used to detect the presence of an analyte by examining the emissions from the substrate when irradiated with optical energy. SERS emissions, or spectra, have been used to detect and identify trace organics and as a detection method in gas chromatography, liquid chromatography, and thin layer chromatography. Electro chemical SERS and SERS of chemically modified surfaces have been used to detect aromatic compounds and chlorinated hydrocarbons and other organic contaminants of environmental concern in the ppb to ppm range. SERS analysis generally requires bulky equipment and typically is performed in a laboratory setting. However, there are many applications in which it would be desirable to detect the presence of analytes in other than laboratory environments. A SERS sensor that is easily transportable and that may be used in the field would be desirable.